tools: support backslash as hierarchy separator for folderspec

Author: jengelh

doc/gromox-mbop.8

@@ -381,6 +381,9 @@ sequence of subordinate folder names
 a folder path starting with a fixed symbolic name, optionally followed by a
 slash-separated sequence of subordinate folder names
 .PP
+The backslash may be used as a hierarchy separator instead; in any case, the
+chosen separator must be used consistently in the entire path.
+.PP
 The recognized strings are: CALENDAR, COMMON_VIEWS, CONFLICTS, CONTACTS,
 DEFERRED_ACTION, DELETED (TRASH, WASTEBASKET), DRAFT, FINDER, INBOX,
 IPM_SUBTREE, JOURNAL, JUNK, LOCAL_FAILURES, NOTES, OUTBOX, SENT,
@@ -399,5 +402,8 @@ Using the MAPI root: /Top of Information Store/Sent Items/2022
 Using a symbolic name: IPM_SUBTREE/Sent Items/2022
 .IP \(bu 4
 Using a symbolic name: SENT/2022
+.IP \(bu 4
+Referencing a folder with a slash can be done by using backslash as the
+hierarchy separator: SENT\\Winter break 2022/2023
 .SH See also
 \fBgromox\fP(7)

tools/genimport.cpp

@@ -605,7 +605,10 @@ eid_t gi_lookup_eid_by_name(const char *dir, const char *name)
 	if (end != name && *znul(end) == '\0')
 		return rop_util_make_eid_ex(1, pure_id);
 
-	auto pathcomp = gx_split(name, '/');
+	const char *sep = strpbrk(name, "/\\"); /* CONST-STRCHR-MARKER */
+	if (sep == nullptr)
+		sep = "/";
+	auto pathcomp = gx_split(name, *sep);
 	if (pathcomp.size() == 0)
 		return 0;
 	auto ptr = std::lower_bound(std::begin(fld_special_names), std::end(fld_special_names),